Art of casting ingots



F. E. McKENNA.

ART OF CASTING mews.

APPLlCATlON FILED MAR. 17. 1916.

Patented Aug. 16, 1921.

FRANK E. MOKENNA, OF LOCKPORT, NEW YORK.

ART OF CASTING INGOTS.

Specification of Letters Patent.

Patented Aug. 16, 1921.

Application filed March 17, 1916. Serial No. 84,924.

T 0 all whom it may concern.-

Be it known that I, FRANK E. MoKnNNA, a citizen of the United States, and a resident of Lockport, in the county of Niagara and State of New Yorlg, have invented an Improvement in the Art of Castir. g Ingots, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to the art of casting ingots and its purpose is to provide such a method'of forming ingots that they may be of uniform and homogeneous structure without open spaces or pipes therein. By the practice of my invention an ingot is provided which consists entirely of solid metal and which does not need to be cropped in order to eliminate metal of a faulty physical structure.

11y invention will be best understood by reference to the following description taken in connection with the accompanying drawings, wherein I have illustrated diagrammatically one manner in which my invention may be practised in order to obtain the improved results set forth and wherein Figures 1, 2 aiid 3 are diagrammatic views in vertical section showing successive steps in molding the ingot; and

ig. 4 is a perspective view of the product.

My invention is particularly applicable to the production of ingots of crucible steel and for clearness of-description I will hereinafter in this specification refer to steel specifically. Referring now to Fig. 1, I have therein illustrated an ingot mold comprising the body 1 and the base 2. When a body of steel such as 3 is poured into the mold and begins to solidify the outer parts of the ingot will become solid first. As the metal solidifies it shrinks in volume and therefore there is a tendency for the inner 1 core of molten metal to draw away from the center of the mold as it hardens and leave an open space or pipe therein. As the heat is conducted away from the bottom of the ingot by the base 2 of the mold the bottom of the ingot will be solid and the pipe will generally consist of an irregular hole extending from the top surface of the mass in a more or less conical form.

It is impossible to utilize the part of the ingot which contains the pipe in ordinary processes sincethe walls of the metal about the pipe will not join when the steel is rolled and the finished article will have a permanent fault therein. It is therefore necessary to crop the ingot, that is, to cut away the upper portion thereof which contains the pipe and to use only the bottom part which alone is of homogeneous structure. My invention minimizes this waste of material.

According to one practicable method embodying this invention, a body of steel 3 is poured or teemed into the mold 1 in any convenient way to form the body portion of the ingot as illustrated in Fig. 1. After the metal 3 has been teemed a cap piece 4, which may be lined with fire-brick or composed of any suitable insulating material, and having the upstanding neck or sinkhead mold 5 is assembled with the mold 1, preferably so that the sink-head mold 5 is directly over the central part of the ingot. I next introduce a suitable flux 6 (Fig. 2) into the mold and for this purpose I preferably utilize a neutral substance which does not deleteriously affect the steel itself. I find anhydrous borax, obtained by the heating of borax crystals, to be desirable. This flux is introduced in any desirable manner, for example, by placin it in powdered form in a suitable container which will be destroyed by the hot metal, such as a paper envelop. After the introduction of the flux a second volume of steel is teemed through the sink-head mold 5 into contact with the main body of steel in the mold 1.

My present understanding of the operation of the above described process is that the interposing of the borax or its substitute between the first and the second pourings of steel, contributes to maintain the upper portion of the first pouring for the main body portion 3 suitably fluid and otherwise in a proper condition to receive and unite with the second pouring 7 to form a homogeneous body of metal at the point where ordinarly the pipe would occur.

\Vhether or not my theory just stated be correct, it is the fact that said process produces an ingot of which the main body portion 3 (Fig. 4) is substantially homogeneous and in physical structure the occurrence of pipes or cavities therein is very largely eliminated. Therefore, it will be unnecessary, in most cases, to crop or remove any portion of the ingot, and only the sink-head 7 which is a column of metal of much smaller cross-section than the ingot itself and which may have a slight pipe or cavity in the top thereof, needs to be cut away. As a result a great economy is affected and it is possible to proportion ingots accurately in any desired weight and for any desired use as it is possible to castthem to the full volume of the mold Without material defects of physical structure.

I believe that bythe practice of my invention as embodied in a method or process it is for the first time-possible to produce with regularity perfect ingots, each one of'which is a complete solid in form of the mold withand reentrant portions or cavities and of homogeneous physical structure throughout. In particular I find it possible to attain this result with high carbon steel such as is used for tools. fered the greatest problem in casting and the waste of cropping-Was the greatest as the pipes'were larger than in lower' grade steels.

I have described in some detail one method of practising my invention and in doing so have. used specific words in referringto the various'i'steps taken and devices employed. It will be understood,however, that I have done so with a descriptive rather than a defining purpose-and that the particular steps and devices mentioned are illustrative only.

This steel has hitherto of- What I do claim and desire to secure by Letters Patent is 1. A process of casting steel ingots applicable in particular to crucible steels comprising the following steps:

body of metal substantially to filltlie mold,

adding anhydrous borax' before complete solidification of said body, and teeming a second volume of like metal providing a sinlc head centrally of v the ingot homogeneously united with-the metal ot the first teemi ngthrough the-action of the borax Intestimony whereof I have signed my name to this specification, in the presence of two subscribing Witnesses FRANK E. Marianna Vitnesses i i LAUR N E A. JA'NNEY, ROBERT H. KAMMLER.

' teeming a body of metal substantially to fill the mold, 

